aeé 
AQ , Rutilated Quartz Crystals from Vermont, 
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oe 
duced by pees of the surface during the more recent, Pee 
riods of u 
At various points along the range By outburst of. he igneous- 
rocks, mineral veins have been observ The examinations had — 
not been sufficiently minute to prononnes on i productiveness, 
The hypogene rocks observe 
this region of country are: granites, iekiies "hed 
greenstone, and various kinds of t 
T 
rap. 
he highest ridges of the south shore of Lake Superior, situ- ae 
ated in the Chippewa Land District, are represented as formed os 
hornblende rocks, ae ee slates, syenite and trap. ‘These 
are estimated to be over a thousand feet above the lake, a ane: 
situated from ten to sixteen miles from its shore. ° 
0 organic remains had so far been fourid-in the. format ions.of © 
Lake Superior by which to establish their age. Neither had any’. 
localities been discovered, where beds of known geological posi- 
tion might solve the question by indicating the relative. order ty) 
superposition 
The principal mass of sandstone — the oauaiti shiore - 
and west end of Lake Superior in nsin, appears to have a 
* different lithological character from ie "enridutile beneath the 
lower magnesian = on the pega described in the Ist. 
chapter of the report. So far as this ev 
on, it militates Saini the supposition of ‘their geological par- 
allelism 
On the west side of the Mississippi, north of the Winnebago 
Reserve, as far as the St. Peter’s river, the lower magnesian lime- 
stone and pail ete -_ prevail as far as the examina- 
tions had exten 1. Ory out half a degree of longitude, . 
The former of tiBee ale occupies the greatest area. 
Arr. I1.—On Rutilated Quartz Crystals from igi,” and 
Phenomena connected with them; by Francis ALGER 
Member of the American Academy, and of the Society ‘of Nat. 
ural History, Boston. 
in Cambridge, in August, 1849 
=’ ay the Proceedings . the American Association for the Advancement of Science, 
eld i ) 
Mr. Atcer presented a paper on the quartz crystals from Wa- 
_terbury, Vermont, containing acicular or capillary Rutile, and ex- 
ited illustrative specimens of great perfection and beauty. ‘He 
. compared them with other specimens from the Alps and Brazil, 
and pointed out some important phenomena in which they dif- 
ab endic rocks, : 
et Ms . 
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